Method for the production of novel anhydride polycarboxylates

ABSTRACT

Novel polyfunctional compounds and a process for their preparation are disclosed. These compounds and their alkali metal salts are useful metal sequestrants and/or detergent builders. Selected compounds are also intermediates useful in the syntheses of aconitic acid as well as isocitric and alloisocitric acids and their lactones. The novel polyfunctional compounds are obtained from the reaction of maleic anhydride with selected active methylene or methane containing compounds.

This is a division application of Ser. No. 970,840, filed Dec. 18, 1978,now abandoned.

This invention broadly relates to novel polyfunctional compounds and aprocess for their preparation. The novel compounds may be converted intocis and trans aconitic acid and into a racemic mixture of isocitricacid, alloisocitric acid and the lactones of isocitric acid andalloisocitric acid. These compounds may also be saponified to formalkali metal salts corresponding to the particular compound employed.These salts, in turn, are metal sequestering agents and/or detergentbuilders. In the preferred embodiments the polyfunctional compounds areconverted into either cis and trans aconitic acid or into a racemicmixture of isocitric acid, alloisocitric acid and the lactones ofisocitric acid, alloisocitric acid as well as the lactones of cis andtrans aconitic acid. These compounds are useful as food acidulants andmetal ion sequestrants. The alkali metal, ammonium and substitutedammonium salts of isocitric acid, alloisocitric acid and cis and transaconitic acid have utility both as metal ion sequestrants and detergentbuilders.

The reaction of active hydrogen compounds such as those containingmethylene or methine moieties with unsaturated acid derivatives is knownand is generally accomplished by means of the well known Michaelreaction. This reaction is considered thoroughly in Chapter 3 of Volume10 of the publication entitled "Organic Reactions" edited by John Wileyand Sons, Inc. In its original sense, as described in the publication,this reaction involves the addition of a donor moiety containing analpha-hydrogen atom in a system ##STR1## to a carbon-carbon double bondwhich forms part of a conjugated acceptor system of general formula##STR2## The addition proceeds under the influence of alkaline or basiccatalysis.

Inherently in the Michael reaction, the donor moiety under the influenceof the basic catalysis (sodium metal is a catalyst of choice) forms ananion which in turn reacts with the beta carbon of the acceptor system.Through the use of this reaction a series of compounds have beenprepared. A listing of a large number of these reactions and reactionproducts appears on pages 271-544 of the above-mentioned publication.The reaction in certain selected instances does not require an addedcatalyst because one of the reactants contains its own basic function.The Michael reaction, thus, is extremely useful for the synthesis ofselected compounds. However, difficulties arise in attempting to carryout the Michael reaction with acid anhydrides such as maleic anhydride.The sodium catalyst tends to react with the anhydride group, thuspreventing the desired reaction from taking place. Use of typicalMichael addition catalysts results in either no reaction or the wrongreaction taking place.

Berner, J. Chem. Soc. 1052 (1946) describes an uncatalyzed reactionbetween maleic anhydride and ethyl acetoacetate. Analysis of the productshowed that a reaction had taken place between two molecules of maleicanhydride and one molecule of ethyl acetoacetate. Bird and Molton,Tetrahedron Letters No. 17, p. 1891 (1966) further describe thisreaction product, and propose that a Michael addition is the first stepof the reaction. This mechanism proposed by Bird, et al however wasrefuted by Berner and Kolsaker in Tetrahedron, Volume 24 p. 1199 (1968).

With reference to preparation of aconitic acid, and isocitric acid,alloisocitric acid and their lactones, prior art processes have beenpractically limited to natural fermentation. Although some syntheticmethods have been proposed in the literature such as in the article byMichael, J. pr. Chem. 49 (ii), 21 (1894), Pucher and Vickery, J. Biol.Chem. 163 169-184 (1946) and Gawron et al., J.A.C.S. 80 5856-5860(1958), none of these methods appear to have been commercialized.

U.S. application Ser. No. 642,850, filed Dec. 22, 1975, now U.S. Pat.No. 4,123,458, discloses a synthetic route for the preparation ofaconitic acid, and isocitric and alloisocitric acids and their lactones,utilizing novel compounds produced by the uncatalyzed reaction of activehydrogen containing compounds with certain maleic acid ester salts. Thisprocess requires the conversion of maleic anhydride to an ester.

It can thus be seen that a catalyzed Michael reaction using maleicanhydride and a methylene or methine containing compound has notheretofore been accomplished. The prior art has now been able to preparefrom these starting materials, polyfunctional compounds which may bereacted to form novel 5-member lactones, and further reacted to formisocitric acid and alloisocitric acid and their lactones.

Accordingly, an object of the present invention is to provide a processfor producing novel polyfunctional compounds by adding an activemethylene or an active methine compound across the double bond of maleicanhydride.

A further object is to produce a novel polyfunctional compound which maybe converted into cis and trans aconitic acid or into a mixture ofisocitric acid, alloisocitric acid and the lactones of isocitric acidand alloisocitric acid as well as salts of these acids.

Yet another object is to provide a novel method for preparing novelpolyfunctional compounds which can be converted into metal ionsequestrants and detergent builders.

Other objects and advantages will appear as the description proceeds.

The attainment of the above objects is made possible by this inventionwhich includes novel polyfunctional compounds and a process for theirpreparation. These novel compounds are anhydrides and acids having thegeneral formulas: ##STR3## wherein:

X is COOR, CN or H and R is methyl or ethyl;

Y is COOR', CN, NO₂ or COCH₃ and R' is methyl or ethyl; and

Q is OH, H or CH₃.

Process For Preparing Novel Polyfunctional Anhydrides

The instant process involves a catalyzed reaction between maleicanhydride ##STR4## and an active methylene or methine containingcompound of the formula: ##STR5## wherein X, Y and Q are as previouslydefined. The reaction which takes place is: ##STR6## This reactionshould take place under substantially anhydrous conditions.

An alkali metal acetate, such as sodium, potassium, or lithium acetatemust be present as a catalyst; without the proper catalyst, the properreaction products will not be obtained. Although lithium acetate doesfunction as a catalyst, the presence of water of crystallization in thissalt slows the reaction rate and requires the use of external heating.Examples of compounds which do not function as catalysts in thisreaction are calcium acetate, sodium metal, pyridine, triethylamine and1,4-diazabicyclo-(2,2,2) octane.

Examples of the methylene or methine containing compounds which reactwith maleic anhydride include diethyl and dimethyl malonate, diethylmethyl malonate, methyl cyanoacetate, nitroethane and dimethyltartronate. Active methylene-containing compounds which do not reactwith maleic anhydride are phenylacetonitrile, phenyl methyl acetate, andhigher (e.g. dibutyl) esters of malonic acid.

The preferred solvents for carrying out the above reaction are theactive methylene or methine containing compounds themselves, due to thesolubility of the acetate catalyst in these compounds. Other solventswhich may be used include dioxane, tetrahydrofuran, tetrahydropyran,dimethoxyethane, diethoxyethane, dimethylsulfoxide, benzene and toluene.Solvents which react with maleic anhydride, such as hydroxylic solventsand dimethyl formamide, should be avoided. In cases where the catalystis not highly soluble in the solvent, the reaction rate will be slower,and higher temperatures must be used.

The ratio of methylene or methine containing compounds to maleicanhydride must be at least about 1:1 to insure completion of thereaction, and may range as high as about 10:1 to obtain a reasonablesolution viscosity. The preferred range is about 3:1 to about 5:1.

Reaction temperatures may range from about 25° C., to insure areasonable reaction rate, to about 150° C. Too high a temperatureresults in excessive degradation of reactants and undesired sidereactions. The preferred temperature range is about 50° C. to about 100°C. In some cases no external source of heat will be necessary due to theexothermic nature of the reaction; cooling, in fact, may be necessary.

The anhydride reaction product (I) hydrolyzes in water to give thediacid: ##STR7## wherein X, Y and Q are as previously defined. Salts ofcompound (II) may be prepared by neutralization of the diacid.

These diacids and their alkali metal salts are useful as metal ionsequestrants and/or detergent builders. Selected diacids of the aboveformula also serve as intermediates useful in the preparation ofaconitic acid, isocitric acid, alloisocitric acid, and the lactones ofisocitric acid and alloisocitric acids.

Halogenation Of Selected Polyfunctional Compounds

Selected compounds of formula II having the formula ##STR8## wherein Rand R' are as previously defined may be halogenated with hypochlorousacid, hypobromous acid, sodium hypochlorite, sodium hypobromite andchlorine or bromine in aqueous solutions or mixed aqueous/methanolicsolutions at pH's of about 2 to about 8 to produce compounds having theformula ##STR9## wherein R and R' are as previously defined and Z is Bror Cl.

The halogenation process is preferably carried out in an aqueousreaction medium. The compound of formula IIA is introduced into areaction vessel with water and, while stirring the mixture, a solutionof a compound capable of generating HOZ (wherein Z=Cl or Br) is slowlyadded. The amount of reaction medium (i.e. water) used is not criticaland is generally from about 50 to about 95% by weight of the totalinitial reaction mixture (i.e. compound IIA plus water). The HOZrequired is conveniently generated from an alkali metal or alkalineearth metal hypohalite by acidification with a mineral acid solutionsuch as hydrochloric or hydrobromic acid. Sodium hypochlorite or sodiumhypobromite solutions are readily available as 5-15% solutions and arereadily employed in this process. When the latter are used, the pH ofthe halogenation reaction mixture is controlled below about pH 8 andpreferably between about 5 and about 7 by the simultaneous addition of amineral acid. If bromine or chlorine is used in the halogenationreaction either directly or as bromine or chlorine water, the pH of thehalogenation reaction mixture is maintained in the above range by theaddition of alkali metal carbonates or hydroxides. The preferred pHrange is utilized to maintain reasonable reaction rates.

The amount of HOZ required in the halogenation process is about 1 toabout 1.1 moles per mole of the compound of formula IIA. If asubstantially greater ratio of HOZ than 1.1 moles per mole of thecompound of formula IIA is utilized, it will not affect formation of theproduct but is uneconomical. If substantially less than one mole isemployed, the reaction will not proceed to completion.

The temperature of the halogenation process is usually in the range fromabout 0° to about 50° C. to avoid premature decarboxylation prior tohalogenation of the compound and to avoid excessive loss of halogenwhich is in equilibrium with the hypohalous acid. Ambient temperaturesare preferred as a matter of practicality and to keep side reactions toa minimum. After addition of the HOZ reactant is complete, the reactionis monitored by periodic sampling and analysis by NMR. Thecharacteristic NMR frequency of the methylene protons will shift fromhigh field in the case of the compound of formula IIA to a lower fieldas the halogenated compound of formula IV is formed in the reactionmixture. When the desired degree of halogenation is obtained, thecompound of formula IV which is water soluble is isolated in its acidform by conventional methods involving acidification of the reactionmixture and recovery of the compound by, for example, extraction with asuitable organic solvent such as acetone.

Conversion of Selected Halogenated Polyfunctional Compounds Into AMixture of Cis and Trans Aconitic Acid

Under strongly alkaline conditions, the compounds of formula IV may beconverted to a propene-1,1,2,3-tetracarboxylate, which uponacidification decarboxylates to form aconitic acid (cis and transforms). The tetracarboxylate formation appears to proceed by means of alactone intermediate (intramolecular lactonization) formed by theelimination of an alkaline earth metal halide. The lactone intermediateformula VI is converted to a hydroxy propane tetracarboxylateintermediate which, with elimination of water, forms the propenetetracarboxylate. The entire reaction scheme is exemplified as follows:##STR10##

In the above reaction scheme, R and R' are independently methyl orethyl.

In the practice of the above synthetic method, an aqueous solution ofthe formula IV compound is neutralized and made alkaline to a pH ofabout 10 to about 12.6, preferably from about 11 to about 12, by theslow addition of an alkaline earth metal hydroxide selected from thegroup Ca(OH)₂, Sr(OH)₂ and Ba(OH)₂, preferably Ca(OH)₂. The alkalinesolution is heated at about 25° C. to about 100° C. preferably about 50°C. to about 70° C. until lactonization, saponification and dehydrationare complete, i.e. about 1/2 hour to 2 hours. The reaction is preferablymonitored by NMR. This is done by sampling the solution, treating withexcess Na₂ CO₃, filtering the insoluble calcium carbonate that forms,evaporating the filtrate and examining the residue by NMR. The reactionis stopped at maximum formation of the propene-1,1,2,3-tetracarboxylatesalt (V) by observing the intensity of the chemical shift of themethylene protons on carbon 3 at about 3.34δ. The tetracarboxylatecalcium salt in the reaction mixture is then treated with dilute mineralacid to liberate the free acid which then undergoes decarboxylation toproduce a mixture of cis and trans aconitic acids.

Conversion of Selected Halogenated Polyfunctional Compounds Into AMixture of Cis and Trans Aconitic Acid, Isocitric Acid, AlloisocitricAcid and the Lactones of Isocitric Acid And Alloisocitric Acid

In the case where Sr(OH)₂ is reacted with a compound of formula IV, amixture of strontium salts of propene-1,1,2,3-tetracarboxylic acid and1-hydroxypropane-1,1,2,3-tetracarboxylic acid may be formed, byfollowing the reaction by NMR and stopping the reaction at the maximumformation of the propene-1,1,2,3-tetracarboxylate species (i.e. maximumintensity of the chemical shift for the methylene protons on carbon 3).On acidification with an aqueous solution of mineral acid, e.g.hydrochloric acid, or treatment with a cation exchange resin in its acidcycle, decarboxylation occurs to give a mixture of cis and transaconitic acid, isocitric acid, alloisocitric acid and the lactones ofisocitric acid and alloisocitric acid. The mixture of products may beisolated by conventional techniques such as solvent extraction or byevaporation of the water followed by extraction with a suitable solventsuch as acetone and subsequent evaporation of the acetone extract.

In the case where Ba(OH)₂ is used to effect the intramolecularlactonization and saponification of the compounds of structure (IV)described above in the pH range 11-12, the reaction forms predominantlythe 1-hydroxypropane-1,1,2,3-tetracarboxylate species as the bariumsalt. On acidification with an aqueous solution of a mineral acid, e.g.hydrochloric acid, or treatment with a cation exchange resin in the acidcycle, decarboxylation occurs to give a mixture of isocitric acid,alloisocitric acid and the lactones of isocitric acid and alloisocitricacid together with some cis and trans aconitic acid.

Conversion of Selected Halogenated Polyfunctional Compounds Into AMixture of Isocitric Acid, Alloisocitric Acid and the Lactones Thereof

In the special case where the compounds of structure (IV) are reactedwith Mg(OH)₂ in aqueous medium, a pH of only about 8-10 is achievable.Under these conditions and between temperatures of about 25° C. andabout 105° C., preferably from 90°-105° C., the reaction proceeds bymeans of intramolecular lactonization, saponification (with sufficientMg(OH)₂) and decarboxylation to give a mixture of the magnesium salts ofisocitric and alloisocitric acids. The latter salts may then beconverted into the acid and lactone forms by either treatment with asuitable cation exchange resin or acidification with mineral acid andisolation by conventional techniques such as solvent extraction orevaporation of the water present followed by extraction of the residuewith a solvent such as acetone and subsequent evaporation of the acetoneextract.

Alternatively, the compounds of structure (IV) may be treated underweakly alkaline conditions of about pH 8-10 utilizing an aqueoussolution containing the stoichiometric amount (one equivalent per moleof IV) of alkali metal hydroxide or carbonate or alkaline earth metalhydroxide at temperatures between 25° C. and 100° C. Under theseconditions, intramolecular lactonization and saponification take place.A novel gamma/lactone may be obtained by reducing the pH of the reactionsolution to 1-3, ##STR11## wherein R and R' are, as previously,independently methyl or ethyl. This novel lactone is more stable thanthe betalactone formed in accordance with U.S. application 642,850 filedDec. 22, 1975, and assigned to the assignee hereof. In place of thealkali metal or alkaline earth metal hydroxides, a weak organic basesuch as pyridine or triethylamine may also be reacted with compounds ofstructure IV under anhydrous conditions to produce the same product(i.e. compound VI). Compound VI may be hydrolyzed to form isocitricacid, alloisocitric acid, and their lactones by heating in an acidsolution.

In another embodiment, an aqueous solution of an alkali metal carbonatewith or without an auxiliary organic base such as pyridine is reactedwith a compound of formula IV to produce a compound of formula VII##STR12## wherein R and R' are as previously defined and M is an alkalimetal cation selected from the group lithium, sodium and potassium.

The compounds of structures (VI) and (VII) may be readily hydrolyzed byheating with the appropriate amount of aqueous solution of an alkalimetal hydroxide, alkali metal carbonate or an alkaline earth metalhydroxide at a pH of about 9-11 and preferably about 9 to 10 to producetetracarboxylate salts having the following structure: ##EQU1## whereinM₂ is Li, Na or K or an alkaline earth metal cation selected from thegroup Ca, Sr and Ba and x is 1 or 2 and corresponds to the valence ofthe cation M₂.

The compounds of formula (VIII) wherein M₂ is Ca, Sr or Ba may also betreated with a solution of an alkali metal carbonate to produce thecorresponding alkali metal salts (i.e. formula (VIII) wherein M₂ is Li,Na or K and x=1). The alkali metal salts of formula (VIII) are useful asdetergent builders and metal ion sequestrants.

The compounds of formula (VIII) may each be converted into a mixture ofisocitric acid, alloisocitric acid and the lactones of isocitric acidand alloisocitric acid by acidification with a dilute solution of amineral acid such as hydrochloric acid, whereby decarboxylation occursto produce said mixture of products.

In another preferred embodiment the halogenated species of formula (IV)may be heated with an aqueous solution of mineral acid, e.g. refluxingwith 10% hydrochloric acid for about 1 to about 16 hours tosimultaneously hydrolyze the ester groups, intramolecularly lactonize,and decarboxylate the compound to produce a mixture of isocitric acid,alloisocitric acid and the lactones thereof. The temperature of reactionis about 25° C. to about 110° C., preferably about 90° C. to 100° C. Thereaction is run for a sufficient amount of time to result in the desiredend product, usually about 6 hours to about 10 hours.

The reaction scheme thus is the same as that previously described foraconitic acid up to the product of formula (IV). The remaining sequenceis as follows: ##STR13##

Thus in essence the invention consists of the described processes andcompounds together with selected parameters as fully described herein.The following examples are designed to illustrate but not to limit thepractice of the instant invention. Unless otherwise indicated, allevaporations are done with a roto evaporator and all percentages are byweight.

EXAMPLE 1 Preparation of α-(Dimethylmalonyl)Succinic Acid

50 grams of maleic anhydride (0.50 moles) are dissolved in 100 grams(0.76 moles) of dimethyl malonate and 12.5 g (0.14 moles) of sodiumacetate is added. The reaction is maintained at 25° C. with externalcooling and allowed to proceed overnight. 200 ml 1:1 ether:chloroformare added and the solution is filtered free of sodium acetate. Thesolution is then evaporated down to give a mixture of thedimethylmalonyl succinic anhydride and dimethyl malonate. The anhydridecrystallizes out and is confirmed by NMR analysis.

NMR in CDCl₃ : ##STR14##

(a) CH₂ ABX multiplet at 3.00-3.22δ

(b) CH ABX multiplet at 3.4-3.7δ

(c)(c') CH₃ at 3.76 and 3.79δ

(d) CH doublet at 4.18δ

Melting point: 125.5° C.

IR: band at 5.38 for 5-membered anhydride.

One gram of the anhydride is dissolved in 10 ml water to give the acid,and is evaporated to dryness.

NMR in CDCl₃ : ##STR15##

(a) CH₂ ABX doublet at 2.9-3.1δ

(b) CH ABX multiplet at 3.6-4.0δ

(c) CH₃ singlet at 4.0δ

(d) CH doublet centered at 4.29δ

Melting point: 92.2° C.

EXAMPLE 2 Preparation of α-(Dimethylmalonyl)succinic Anhydride

20 grams (0.2 moles) maleic anhydride are dissolved in 50 grams (0.38moles) dimethyl malonate. 2 grams (0.02 mole) potassium acetate areadded and the solution is stirred and allowed to stand overnight. 100 mlether are added and the solution is filtered. The filtrate is evaporatedto give 18 grams of product.

EXAMPLE 3 Preparation of α-(Dimethylmalonyl)succinic Acid

Example 1 is repeated using 1 gram (0.01 moles) lithium acetate as acatalyst, in place of sodium acetate, with 10 grams maleic anhydride and16 grams dimethyl malonate. The reactants are heated to 75° C. for 8hours, and the reaction product converted to the acid form.

EXAMPLE 4 Preparation of α-(Dimethylmalonyl)succinic Acid

10 grams (0.1 mole) maleic anhydride and 13.2 grams dimethyl malonateare dissolved in 50 ml dioxane. Two grams sodium acetate are added andthe solution is stirred for 1 hour. Since the reaction rate isnegligible, the reactants are heated to 85°-90° C. for 6 hours, and thenallowed to stand overnight. The solution is evaporated to dryness, theresidue dissolved in 200 ml water, and the solution filtered. Uponevaporation of the solution to dryness, 14 grams (56.4% yield) ofproduct are recovered.

EXAMPLE 5 Preparation of α-(Dimethylmalonyl)succinic Acid

20 grams (0.2 mole) maleic anhydride are dissolved in 42 grams (0.26mole) diethyl malonate, and 5 grams (0.06 mole) sodium acetate areadded. The temperature is maintained at 50° C. for one-half hour. 100 mlether are added, and the solution is filtered and evaporated. Thesolution is extracted with petroleum ether to remove traces of diethylmalonate. 10.5 grams of anhydride are recovered and characterized byNMR.

NMR in CDCl₃ : ##STR16##

(a) CH₃ two triplets at 1.20-2.55δ

(b) CH ABX multiplet at 3.00-3.24δ

(c) CH ABX multiplet at 3.32-3.93δ

(d) CH doublet under the quartets (b)-(c)

(e) CH₂ 2 quartets at 4.0-4.5δ

Two grams of the anhydride are dissolved in 50 ml water and the solutionevaporated to dryness. The resultant acid is characterized by NMR.

NMR in D₂ O: ##STR17##

(a) CH₃ triplet centered at 1.25δ

(b) CH₂ ABX doublet at 2.65-2.95δ

(c) CH ABX multiplet at 3.40-3.80δ

(d) CH doublet centered at 4.0δ

(e) CH₂ quartet centered at 4.16δ DHO at 4.74δ.

EXAMPLE 6 Preparation of α-(Diethylmalonyl)succinic Acid

80 grams (0.82 mole) malonic anhydride, 230 grams (1.4 moles) diethylmalonate and 20 grams (0.23 mole) sodium acetate are combined, stirredfor 1 hour and allowed to stand overnight. 224 grams of 12% hydrochloricacid are added and the solution is evaporated down to a syrup. The syrupis dissolved in 600 ml water and extracted with carbon tetrachlorideuntil the CCl₄ fraction contains no diethyl malonate. 160.6 grams (73.3%yield) of acid product are obtained.

EXAMPLE 7 Preparation of α-(Acetyl Carbomethoxy Methynyl)succinic Acid

20 grams (0.2 mole) maleic anhydride are dissolved in 100 grams (0.86mole) methyl acetoacetate. Five grams (0.06 mole) sodium acetate areadded slowly, the temperature rising to 95° C. The solution is stirredfor eight hours. 306 grams 2% hydrochloric acid are added and the waterand excess acetoacetate are removed under vacuum. The residue isdissolved in acetone, the solution filtered, and evaporated. The residueis dissolved in 200 ml water and excess acetoacetate is removed byextraction with carbon tetrachloride. 31 grams of acid are obtained andcharacterized.

NMR in D₂ O. ##STR18##

(a) CH₃ singlet at 1.82δ

(b) CH₂ ABX multiplet at 2.72-3.20δ

(c) CH ABX multiplet at 3.40-3.90δ

(d) CH₃ singlet at 3.96δ

(e) CH hidden under CH₃ 's DHO at 4.86δ.

The NMR also shows evidence of the formation of another compound,probably of the formula ##STR19##

EXAMPLE 8 Preparation of α-(Cyano Carbomethoxy Methinyl)succinic Acid

20 grams (0.2 moles) maleic anhydride are dissolved in 90 grams (0.91moles) methyl cyanoacetate. Five grams (0.06 mole) sodium acetate areadded and the solution is stirred for eight hours. 206 grams, 32hydrochloric acid are added and the solution extracted with carbontetrachloride until the CCl₄ contains no trace of cyanoacetate. Thewater solution is evaporated to dryness, the residue is dissolved inacetone, and the solution filtered. The acetone solution is evaporatedand 0.47 grams of product obtained.

NMR in D₂ O: ##STR20##

(a) CH₂ ABX multiplet at 2.24-2.91δ

(b) CH ABX multiplet at 3.15-3.49δ

(c) CH₃ singlet at 3.58δ

(d) hidden

EXAMPLE 9 Preparation of α-(Diethyl Methyl Malonyl)succinic Acid

20 grams (0.2 moles) maleic anhydride are dissolved in 80 grams (0.46mole) diethyl methyl malonate. 7.5 grams (0.087 mole) sodium acetate areadded, and the solution is heated to 60°-70° C. for 3-4 hours, thenallowed to stand overnight. 209 grams 4.6% HCl is added, and thesolution is evaporated. The residue is dissolved in acetone, filteredand evaporated to dryness. The residue is dissolved in 300 ml water, andextracted with CCl₄ to remove unreacted diethyl methyl malonate. Thewater solution is evaporated to obtain 39.2 grams of product (67%yield).

NMR in CDCl₃ : ##STR21##

(a) CH₃ triplet centered at 1.38δ

(b) CH₃ singlet at 1.53δ

(c) CH₂ ABX multiplet at 2.6-3.04δ

(d) CH ABX multiplet at 3.60-3.95δ

(e) CH₂ quartet centered at 4.25δ

EXAMPLE 10 Preparation of α-(1-Nitroethyl)succinic Acid

20 grams maleic anhydride are dissolved in 75 grams (1 mole)nitroethane. 7.5 grams (0.086 mole) sodium acetate are added and thesolution is refluxed for 7 hours at about 115° C. 209 grams 4.6% HCl areadded and the solution is evaporated down. The residue is dissolved inacetone and filtered and the filtrate is evaporated down. A mixture ofproduct and maleic acid is obtained.

NMR in D₂ O: ##STR22##

(a) CH₃ doublet centered at 2.04δ

(b) (c) CH₂, CH at 3.2-3.6δ

(d) CH doublet of doublets at 5.13δ

EXAMPLE 11 Preparation of α-(Dimethyl Tartronyl)succinic Anhydride

9.9 grams (0.1 mole) of maleic anhydride and 2 grams sodium acetate aredissolved in 15 grams (0.1 mole) dimethyl tartronate. The solution isheated to 100° C. for one-half hour, then to 125° C. for anotherone-half hour. A sample is removed for NMR analysis. The reactionmixture is retained for use in Example 12.

NMR in CDCl₃ : ##STR23##

(a) CH₂ ABX multiplet at 2.60-3.02δ

(b) CH₃ singlet at 3.91δ

(c) hidden beneath CH₃ 's

EXAMPLE 12 Preparation of Isocitric/Alloisocitric Acid and theirLactones

To the remaining reaction mixture of Example 11 is added 340 grams of12% HCl, and the solution is refluxed for 3 hours. The solution is thenevaporated to dryness and the residue extracted with 200 ml acetone andfiltered. The acetone is evaporated and 16.8 grams of product arerecovered.

EXAMPLE 13 Preparation of α-(Dimethylchlorlomalonyl)succinic Acid

24.8 grams (0.1 mole) of α-(dimethylmalonyl)succinic acid prepared as inExample 1 are dissolved in 200 ml water. 30 grams of 5.2% sodiumhypochlorite solution are added slowly to a pH of 5.4, and the solutionis acidified to pH 2.0. The solution is then evaporated to dryness, andthe residue dissolved in 200 ml acetone, and that solution filtered. Theacetone solution is evaporated down to produce 23 grams of product (82%yield).

NMR in D₂ O: ##STR24##

(a) CH₂ ABX doublet at 2.90-3.15δ

(b) CH₃ singlet at 4.04δ

(c) ABX triplet at 4.1-4.39δ

DHO at 4.71δ

EXAMPLE 14 Preparation of α-(Dimethyl Hydroxymalonyl)succinic Acid GammaLactone

24.8 grams (0.1 mole) of α-(dimethylmalonyl)succinic acid produced as inExample 1, is dissolved in 200 ml water. 300 grams 5% sodiumhypochlorite solution are added slowly at a pH of 5.4. The reactionmixture is stirred for 15 minutes and 10 grams sodium carbonate areadded to a pH of 8.6-9.0. The solution is stirred at 80°-85° C. forone-half hour, cooled and acidified with 10% HCl to a pH of 1.0. Thesolution is then evaporated, and the residue dissolved in acetone andfiltered. 17 grams of product are obtained by evaporating the acetone.

NMR in D₂ O: ##STR25##

(a) CH₂ ABX multiplet at 2.70-3.01δ

(b) CH₃ singlet at 3.72δ

(c) CH ABX multiplet at 3.75-4.04δ DHO at 4.63δ

EXAMPLE 15 Preparation of α-(Dimethyl Chloromalonyl)succinic Acid

27.6 grams (0.1 mole) of diethyl malonyl succinic acid as prepared inExample 5 are dissolved in 200 ml water. 400 ml 5% sodium hypochloritesolution is added slowly to pH 5.3 and the solution is stirred for 1/2hour. 10% HCl is added to pH 1.3 and the solution evaporated to dryness.The residue is dissolved in 200 ml acetone, and the solution filteredand evaporated. 29 grams (94% yield) of product are obtained.

NMR is D₂ O: ##STR26##

(a) CH₃ triplet centered at 1.27δ

(b) CH₂ ABX multiplet at 2.71δ

(c) CH ABX multiplet at 4.05-4.29δ

(d) CH₂ quartet centered at 4.40δ DHO at 4.75δ

EXAMPLE 16 Preparation of α-(Diethyl Bromomalonyl)succinic Acid

27.6 grams (0.1 mole) of α-(diethyl malonyl)succinic acid as prepared inExample 5 are dissolved in 200 ml water. 10 g of Na₂ CO₃ are added to apH of 5.0 and 27 grams of bromine are added slowly, while the pH ismaintained at 4.0-4.5 with additional Na₂ CO₃. After stirring for 1/2hour, the solution is acidified to pH 1.3 with 10% HCl, and evaporatedto dryness. The residue is dissolved in acetone and the solution isfiltered and evaporated in vacuo to give 30 grams of product containingsome unreacted product of Example 3.

NMR in D₂ O: ##STR27##

(a) CH₃ triplet centered at 1.32δ

(b) CH₂ ABX multiplet at 3-3.23δ

(c) CH hidden

(d) CH₂ two quartets; one centered at 4.40δ, one at 4.46δ DHO at 4.82δ.

EXAMPLE 17 Preparation of α-(2-Hydroxy Disodium Malonyl) DisodiumSuccinate

9.4 grams (0.03 mole) of α-(di-ethyl chloro malonyl)succinic acid, asprepared in Example 15, is mixed with 75 ml water and 4.4 g (0.06 mole)of Ca(OH)₂. After 15 minutes an additional 3 grams of Ca(OH)₂ is addedto maintain the pH at 9.5-10.0. The resulting mixture is heated at60°-70° C. for 4 hours while stirring and maintaining the pH at 9.5-10.0by further addition of Ca(OH)₂ as required. Sodium carbonate, 0.1 mole,is then added and the reaction mixture is stirred at 60°-70° C. for 15minutes. The solution is filtered to remove CaCO₃ and the pH of thefiltrate is adjusted to 9.0 with dilute hydrochloric acid. Afterevaporation of the water, a residue of the α-(2-hydroxy disodiummalonyl) disodium succinate containing traces of sodium chloride isobtained. The structure of the product is confirmed by NMR analysis (D₂O): ##STR28##

(a) CH₂ 2.25-2.7δ

(b) H 3.0-3.9δ.

EXAMPLE 18 Preparation of Isocitric and Alloisocitric Acid LactonesProcedure A

One gram of the product prepared in Example 17 above is acidified withdilute HCl (10δ, (with liberation of CO₂) and evaporated to dryness invacuo. The product consists of a mixture of isocitric and alloisocitricacid lactones by NMR analysis (D₂ O): ##STR29##

(a) CH₂ ABX multiplet at 2.94-3.28δ

(b) H ABX multiplet at 3.78-4.19δ

(c) H doublet at 5.38-5.58δ

(c')H doublet at 4.3-4.5δ (traces of isocitric acid and alloisocitricacid).

Procedure B

Fifty grams of the compound prepared in Example 17, i.e. the sodium saltof α-(diethyl chloromalonyl)succinate is dissolved in 100 ml of water towhich 10 ml of concentrated hydrochloric acid has been added. Thesolution is refluxed for 16 hours and then evaporated in vacuo to leavea solid residue consisting of a 1:1 mixture of the lactones of isocitricacid and alloisocitric acid (structure determined by NMR analysis-D₂ O).

EXAMPLE 19 Preparation of Tetrasodium Propene 1,1,2,3-Tetracarboxylate

10 grams (0.036 moles) of α-(dimethyl chloromalonyl)succinic acid, asprepared in Example 15, is mixed with 200 ml water. Ca(OH)₂ is thenslowly added at first maintaining the pH at 10.0 and then heating to60°-70° C. until all the ester groups are saponified. A total of 10grams of Ca(OH)₂ is added (pH 11.6) and the slurry is stirred for 2-3hours at 60°-70° C. Thirteen grams of Na₂ CO₃ is then added and themixture is stirred for 15 minutes at 50° C. The precipitated CaCO₃ isfiltered and the filtrate is evaporated to give the tetrasodium propane1,1,2,3-tetracarboxylate. The structure is confirmed by NMR analysis (D₂O):--CH₂ -(a) singlet at 3.34δ. ##STR30##

EXAMPLE 20 Preparation of 1:1 cis:trans Aconitic Acid

Nine grams of the product as prepared in Example 19, i.e. tetrasodiumpropane-1,1,2,3-tetracarboxylate, is dissolved in 100 mls water andacidified with dilute HCl (10%). Liberation of CO₂ is instantaneous. Theresidue, after evaporation of water, is extracted with acetone. Theacetone is evaporated to leave a residue consisting of a 1:1 by weightmixture of cis:trans aconitric acid. The structure of the product isconfirmed by NMR analysis (D₂ O):

cis Aconitic Acid: ##STR31##

(a) CH₂ singlet at 3.44δ

(b) CH singlet at 6.33δ.

trans Aconitic Acid: ##STR32##

(a) CH₂ singlet at 3.80δ

(b) CH singlet at 3.92δ.

EXAMPLE 21 Preparation of Isocitric Acid, Alloisocitric Acid and theirLactones

28 grams (0.1 mole) of α-(dimethyl chloromalonyl)succinic acid, asprepared in Example 15 is mixed with 200 ml water. Sodium hydroxide, 20g (0.05 mole), is added slowly while maintaining the temperature at 60°C. and the pH between 9 and 10. After heating for 3-4 hours at 60° C.,the solution is cooled and acidified to a pH of 1.2 with dilutehydrochloric acid. The heated solution is then evaporated in vacuo andthe residue remaining is extracted with acetone. The acetone extract isthen filtered and the filtrate, evaporated to give a residue of amixture of 1:1 isocitric acid:alloisocitric acid and the lactonesthereof (identified by NMR).

EXAMPLE 22 Preparation of Isocitric Acid, Alloisocitric Acid and theirLactones

15.6 grams (0.05 mole) of α-(diethyl chloromalonyl)succinic acid asprepared in Example 15 is mixed with 200 ml water. 25 grams (0.43 mole)magnesium hydroxide is added slowly while maintaining the reactionmixture at 80°-90° C. and the pH at 9.0. After refluxing the reactionmixture for 2 hours, the solution is cooled and then acidified with 86.2g of 50% sulfuric acid. The acidified solution is evaporated to yield aresidue which is then extracted with acetone. The acetone extract isfiltered and the filtrate evaporated to give a residue consisting of amixture of isocitric acid and alloisocitric acid and the lactonesthereof (identified by NMR).

This invention has been described with respect to certain preferredembodiments and various modifications and variations in the lightthereof will be suggested to persons skilled in the art and are to beincluded within the spirit and purview of this application and the scopeof the appended claims.

What is claimed is:
 1. A lactone of the formula ##STR33## wherein R andR' are independently selected from the group consisting of methyl andethyl.